The high speed intermittent movement of metal strip, for example, the metal strip used to form lead frames for integrated circuit chips, requires rollers that contact the strip with a fairly high contact force. It is practically impossible to prevent such rollers from deforming the strip a little. This being the case, it is necessary to insure that equal rolling pressure is applied on all parts of the strip, so that all parts are elongated by the same amount. Without this force balance, one side of the strip becomes slightly longer, creating a curve in the strip. Accordingly, prior art rollers are usually mounted on adjustable supports, sometimes with springs, so that the rolling force may be continuously adjusted to keep the strip from assuming a curve or warp.
Experience has shown that a great deal of time and effort is consumed in providing adjustments to keep the roller force balanced along its length. The present invention saves this time and effort by providing a roller that is self balancing so as to automatically maintain an even balanced force along the length of the rolling surface.